As I stated in some comment about the subject, it make sense for it to be an inside job. The demand (close the website) was kind of ridiculous for normal hackers. My conspiracy bias make me think the shareholder/CEO wanted to blackmail their user.
The reality may be more simple and dim: a former employee seeking revenge.
I'm looking forward for a former Google employee to dump everyone secret nasty search and email. It will be fun.
So he convinced me it's an inside job...but: If that fails to convince you, then this must: In the first manifesto two names of male members were released. In describing one of them the perpetrator states the he "spitefully" joined Ashley Madison the day after Valentine's Day. Anyone who ever had a significant other knows that women rate Valentine's Day higher than Christmas, and men think so little of it that they have to remind each other the day is nearing. To call an act the day after Valentines Day "spiteful", is a thought that would enter few men's minds. If this does not convince you then you need to get out of the house more often. So apparently no man has ever called a man a scumbag, and also men are unable to grasp that Valentine's Day is considered important by many people in romantic relationships? Those comments make no sense.As to gender of the perpetrator, there were a number of telling signs in the manifestos. The most telling was a statement calling men "scumbags" (for those readers that don't speak American/Canadian English, this is a word that only a woman would ever use to describe men). In a separate section, the perpetrator describes men as cheating dirtbags. I think in any language this would suggest that a woman is speaking.
It's interesting that John McAfee thinks a dump of everything in a MySQL database is harder than producing CSV's. A database dump is a single command. If you have the password for a MySQL server, and no further security measures were in place, you have access to everything stored there. Depending on the company, they could be storing credit cards and stock option allotments on the same server. The scumbag thing did remind me of that I Shot Andy Warhol gal, and the Valentine's Day reference made me think, "Aww, you weird precious sweetie." It could be a woman. But it could be a woman who cracked or acquired a single password, not necessarily an insider who used "guile". Yuck.